The present invention concerns a waterproof, water-vapor-permeable fabric. The object of the present invention is to provide a material which makes it possible to manufacture, both easily and reliably, hats and other accessories and articles of apparel, so that the articles are obtained as products with insured waterproof and moisture-permeable characteristics.
The present invention concerns a material which makes it possible to manufacture hats, shoes, gloves, socks, underwear and other articles of clothing, etc., as products with insured waterproof and moisture-permeable characteristics.
If articles such as hats (and other accessories) and underwear (and other types of clothing) can be produced as articles which are waterproof and moisture permeable, it becomes possible to obtain articles of clothing which keep the body from becoming wet in the rain, and which, at the same time, allow moisture or water vapor arising from perspiration to pass through the material so that this moisture is appropriately dispersed. Such clothing is desirable in that it allows comfortable wear in both of the abovementioned situations.
One method of obtaining such waterproof and moisture-permeable characteristics is as follows: i.e., by rolling or drawing a polytetrafluoroethylene film, it is possible to form a spiderweb-form fibrilized structure with micropores which average approximately 0.2 microns in size, as disclosed in U.S. Pat. No. 3,953,566. Furthermore, this structure is a stable structure in which the microfibrils are stretched between micronodes. The small size of the spaces between the fibrils acts in conjunction with the water-repelling properties of the resin itself so that the material has reliable waterproof characteristics under ordinary pressures. Furthermore, moisture can effectively pass through the aforementioned micropores. Similar structures are being studied and developed using resins other than the abovementioned fluoroethylene resin.
If the aforementioned accessories or articles of clothing are formed using such a waterproof, water-vapor-permeable film or fabric as a material, it is possible to obtain products which are waterproof and water vapor permeable, and such products have very wide practical application.
However, the abovementioned waterproof, water-vapor-permeable material must be formed as a flat sheet-form material, both due to considerations involved in industrial mass production and in order to obtain uniform characteristics. In cases where the aforementioned three-dimensional accessories or articles of clothing are formed from such a flat sheet-form material, it is necessary to cut a considerable number of material parts, and to combine these parts by sewing in order to form a three-dimensional configuration. In the case of configurations which must be especially smooth, it is necessary to use a large number of the aforementioned material parts, and the number of individual sewing processes is correspondingly increased, so that considerable labor must be expended.
Furthermore, in the case of such sewn articles, the painstakingly achieved waterproof structure is destroyed by the needle punctures created in the sewing process, so that the resulting articles are not waterproof. Accordingly, a hole-plugging process is required in order to plug these sewing holes (needle punctures). Thus, in addition to the aforementioned cutting and sewing, a hole-plugging process is required, which increases the labor expended and drives costs up. Furthermore, even if waterproof characteristics are obtained in the areas subjected to the aforementioned hole-plugging process, the moisture permeability of these areas is usually inpeded as a result. At the very least, the waterproof characteristics or water-vapor-permeability (or other properties such as the feel of the material) in the areas subjected to the aforementioned hole-plugging treatment are damaged or altered by the hole-plugging agent used.